<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		输入：<input type="text" id="txt1" /> 转换结果:<input type="text" id="txt1Value" />  
		<input type="button" id="btnTrun" value="转换为数字" onclick="turnNumber()" />
		<input type="button" id="btnClear" value="清除" onclick="clearInput()" />		
		<script>
			// begin====================>
			// 演示字符串进行parseInt的结果  
			c
			function turnNumber(){
				var val1 = document.getElementById('txt1').value;
				if(val1.trim() == ""){
					alert("请输入有效的值");
					return;
				}
				document.getElementById('txt1Value').value = parseInt(val1);
// 				if(confirm("转换结束，是否要清除转换结果?")){
// 					document.getElementById('txt1Value').value = "";
// 				}
			}
			// <<<<<<<<<<<<<<<<<<<<<<<<finish
			
			// 开始演示非字符串类型进行强制转换
			// 1
			console.log(parseInt([1, 2, 3]));
			// 3
			console.log(parseInt([3, 2, 1]));
			// NaNc
			console.log(parseInt(['a', 2, 1]));
			// -3
			console.log(parseInt([-3, 2, 1]));
			// -3
			console.log(parseInt([-3, 'a', 'b']));
			// NaN
			console.log(parseInt(" "));
			// NaN
			console.log(parseInt(true));
			// NaN
			console.log(parseInt(false));
			// NaN
			console.log(parseInt(null));
			// NaN
			console.log(parseInt(undefined));
			var obj = {"name": "张恒", "age": 18};
			obj['weight'] = 55;c
			console.log(obj);
			// NaN
			console.log(parseInt(obj));
			// 结束强制转换为int的演示
		</script>
	</body>
</html>
